Engine for rock-drills.



" "Nrrs Startins"y PATENT nnrcr.

PATRICK H. REARDON, OF SAN FRANCISCO, CALIFORNIA;

E NGNE FOR ROCK-DRILLS;

sPEcIilIcATIoN forming part of Letters Patent No. 645,536, dated Marcil 13, ieoo.

Application tiled June 29,v 1899.

To aLZZ whom it may concern,.-

Be it known that I, PATRICK H. REARDeN, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented certain new and useful Improvements in Engines for Rock-Drills; and I do hereby declare the following to be a full, clear, and exact description of the same.

Y This invention relates to the class of rockdrills such as are actuated usually by air or steam..

It consists in the novel construction and combination of the several parts hereinafter fully described and claimed.

The device is illustrated in the accompanying drawings, in which- Figure 1 is a sectional elevation. Fig. 2 is a cross-section through lines :n and y of Fig. l. Fig. 3 is a cross-section through line ,e of

Fig. 2. Fig. 4 is a plan view of the cam andl the cam-handle. Fig. 5 is a perspective view of one form of pawl. Fig. 6 is a cross-section showing another form of the pawls and ratchet. Fig. 7 is a perspective view of the slotted sleeve for the reception of the pawl.

This class of devices, owing to the character of their work and the great velocity and comparative weight of the reciprocating parts, are subjected to excessive wear and tear on some parts, while other parts are not thus taxed. Heretofore owing to undue complication no pressure-relieving device for slidevalves in rock-drills has proven practically successful and a large amount of the work of the actuating iiuid in slide-valve rock-drills is employed in overcoming the friction of the slide-valve. The rough and uneven surface of rock makes it difcult to start a hole with a drill operating with a full stroke of the piston, besides subjecting the device to severe strains and destructive jars. A rapid succession of short sharp blows overcomes this diliiculty. The capability, therefore, in a rock-drill of delivering this character of blow, as well as the full power and full stroke of normal operation, is very desirable. The ratchet-chamber casting,` a comparatively-expensive piece of construction, has heretofore been short-lived, owing to the rapid wear and breakage due to the excessive duty necessarily imposed upon the pawls and their seats.

Serial No. 722,333. (No model.)

Another source of rapid deterioration in rockdrills is the bad alinement of the cylinder with the sliding frame due to improper 'ad- .justment in the slides and .guides to take up the effect of wear. This maladjustment throws the line of shock across the structure, thus introducing destructive strains and undue and disintegrating vibration.

It is obvious that improvements in theform and construction of rock-drills and their component parts which will obviate the diiculties and provide for the requirements thus briefly referred to will add materially to the life and eective utility of such devices. To accomplish this end is, stated generally, the object of the present invention.

More specifically stated, some of the objects are to provide a rock-drill which while drilling under normal conditions gives a full stroke of the drill, vand when the conditions require it short quick strokes may be delivered; also, to provide against breakages incident to the excessive duty required lof the pawls in turning the drill, and also to provide means for maintainingaccurate alinement of the drill with its slide-frame as the slides wear by usage.

Referring to the drawings, VA is a cylinder having a suitable piston B.

C is a valve-chest.

, D is a slide-valve. The valve D is provided with a pressure-relieving device consisting of the boss E on the back of the valve, provided with suitable packing e. slightly tapering to facilitate its ready fitting, the joint being dependent principally upon the packing e. A loose plate F, sliding upon a surface c parallel to the valve-seat', is provided with a-cup or socket f, fitting the boss E and having an outlet or vent f', Between the boss and plate F a spring f2 is interposed to keep the plate F against its seat.

A rocking tappet-arm G, formed substantiallylike an inverted T, is located in a pocket radial to the cylinder. g transverse to the cylinder. The tail or stem of the T `engages with the slide-valve, which it reciprocates by alternate blows of the piston on suitable inclined surfaces of the crossbar of the T.

The piston B has a portion of its length intermediate of its ends reduced in diameter The boss E is shown It oscillates on a pivot Y IOO i pet T-arm G by alternate contact with each end thereof.

Extending from the valve-chest is a springchamber H, preferably of cylindrical form, in which is located a spring-buffer I. Fitted snugly in the chamber H is steam-tight movable plug J, bored out to receive one end of the buffer-spring z', the other end of the spring resting against a collar t" on the buffer. At the end of chamber H is a cam K, whose pivot 7.: is exterior to the chamber. The operative surface of the cam projects into the chamber H and bears against the plug .I A suitable handle K is provided for the cam to partially rotate it. The cylinder A is provided with any suitable drill-rotating mechanism actuated by the reciprocation of the piston. This is shown as the rifle-bar L, with its ratchet-head L', the pawls N and the nut M fitting the rifling of the bar. The pawls may be of any suitable form. I have shown two forms in Figs. 2, 3, 5, and 6; but in whatever form they are made I preferably place them in a sleeve shown in Fig. 7, as illustrated in Figs. 2, 3, and 6. The sleeve O consists of a cylindrical pin bored for a portion of its length to fit the back or cylindrical side of the pawl, which it embraces for more than one-half its diameter. It is slotted to allow the pawl to slide endwise into it, the pawl-lip projecting outward through the slot, as shown in Figs. 2 and 6. This sleeve is shown clearly in Fig. 7. It is longer than the pawl, extending beyond the length of the pawl on each end. It is lprovided with means for preventing its turning when in place, which is preferably, as shown, a flattened extension o, adapted to fit in a similarly-formed socket at the end of the pocket in which it is located, Figs. 3 and 7. The sleeve where it projects beyond the pawl is socketed in the ratchet-chamber end on one end and in the ratchet-chamber cover on the other end.

The drill-cylinder is provided with suitable longitudinal slidestrips P, Fig. 2, preferably made wedge-shaped in section, which are tted to guides Q on the drill-frame, having adj ustable gibs q q. Each guide Q is provided with a longitudinal upwardly-projecting rib Q', forming a positive backing for its gib, and parallel strips q are also provided between the guide Q and the backing Q' to take up the wear on the guides and slides and insure parallelism of the cylinder after such adjustment. Gibholding bolts qz'qa are provided to secure the gibs q q after adjustment, all of which is shown in Fig. 2.

The drill is operated in the ordinary manner of such devices, except when, as in starting a hole, it is desirable to deliver a rapid succession of quick short strokes. Under these conditions the handle K is turned7 thus compressing the spring z' against the buffer-collar, projecting the buffer into the valve chamber in contact with the slide# valve end. The eect of this is that the valve is worked against the resistance of the spring, which is sufficient to return the valve without the assistance of the piston and the valve-tappet rock-arm, with the result that as soon as the piston moves from under the end of the tappet-arm the valve immediately follows and reverses the direction of the steam without Waiting for the piston to make the complete stroke and operate the valve, as it normally does, by contact of lthe piston against the other end of the tappet-arm. The pressure-relieving device on the back of the slide-valve facilitates the operation of the spring-buer by reducing the friction of the valve, and consequently the power necessary to move it.

The functions of the'slotted sleeve are twofold. It serves to secure the pawl in the main casting of thedrill and at the same time pro-V tects the casting from the rapid wear which usually takes place in this part of a drill, as the sleeve may be made of more resistant material than the ratchet-chamber. Furthermore, it forms an easily-renewable wearing part of but little value relatively to the ratchet-chamber. Apart from the advantage derived from its being readily renewed itincreases the area of the surface effected by the thrust of the pawl.

The plate F bearing, as it does, against the stationary surface c and being fitted on the slide-valve D by its socket f and the boss E on the back of the valve, the valve is relieved of the pressure of the actuating fluid over the area of the boss and socket. Any leakage of the actuating fluid into the cup or socket finds its way to the exterior through the small hole or vent in the top of the socket and its continuation to the exterior. (Shown in dotted lines atf, Fig. l.) The springf2 insures the contact of the plate F with its bearingsurface e. p

As heretofore intimated it is exceedingly` important to the life and integrity of the drill that perfect alinement shall be maintained between the longitudinal axes of cylinder and frame. The arrangement of the gibs q q and guides Q with their backing-ribs Q and parallel strips P insure this necessary parallelism as they form con tin uously a practically; solid guide for the drill-slides unaffected by the vibration incident to operation. In their absence, no matter how carefully bolted, this vibration would work the gibs backward and permit of destructive play and lost motion between the cylinder and the frame. These backing ribs and strips provide also against the maladjustment by unskilled operators, such as almost invariably have the management and operation of this character of devices, by making it practically impossible to set the gibs up other than truly parallel.

It is obvious that many changes and modiications will suggest themselves to mechanics to adapt the invention herein to various contoo IIG

haas s ditions of operation without departing from1 the essential character thereof. I therefore do not desire to confine myself to the exact and a suitable valve controlling the actuating iiuid, whereby the piston is reciprocated, means adapted to control said valve whereby the stroke of the piston is lengthened or shortened at will, in combination with means for relieving the pressure on said fluid-controlling valve.

2. A rock-drill comprising a cylinder, a fluid-actuated piston therein and a slide-valve in a suitable valve-chamber adapted to control said iuid, a tappet interposed between said piston and the slide-valve to operate the latter by the motion of the former whereby said piston is re'ciprocated, a pressurereliev ing device on said slidevalve consisting of a stationary surface between which and the valve-seat, the valve is located and a loose plate socketed on the back of the valve bearing against said surface and means for varying the stroke of said piston substantially as described.

3. A rock-drill comprising a cylinder, a Huid-actuated piston therein and a valve controlling the actuating fluid, suitably arranged to be operated by the piston and an adjustable buffer with means adapted to effect the engagement of said buer with the valve,- whereby the valve is moved in one direction by the piston through the intervention of said buffer and means for relieving the pressure on said valve.

4. A rock-drill comprising a cylinder, a iuid-actuated piston therein and a slidevalve controlling the actuating fluid, provided with a pressure-relieving device and a rock-arm interposed between said valve' and piston, whereby the valve is moved by the motion of the piston in one direction directly and a spring adapted to move the valve in the 0pposite direction.

p PATRICK H. REARDON.

Witnesses:

WM. A. HEWITT, A. W. STAUFFER. 

